A conventional retractable pipe structure is shown in FIGS. 8 and 9. The pipe structure 50 has an inner tube 51 and outer tube 52, wherein the inner tube 51 is a resilient unit and the outer tube 52 is not resilient but wrinkled. Two connectors 53 are disposed at two ends of the outer tube 52 and the connector 53 has a connecting portion 531 that has a protruding end 532 at the front portion thereof and a tightening ring 533. A locking section 534 is disposed at the upper portion of the connecting portion 531 and a locking sleeve 54 is provided and has a protruding unit 541 corresponding to the protruding end 532 of the connecting portion 531. So, when assembling the pipe, the inner tube 51 is connecting with the connecting portion 531 of the connector 53 and the inner tube 51 is restricted by the protruding end 532. The tightening ring 533 covers the inner tube 51 and the outer tube 52 is outside the tightening ring 533. Finally, the locking sleeve 54 engages with the locking section 534 to secure the inner tube 51, outer tube 52 and connector 53 through the tightening ring 533 and the locking sleeve 54.
The conventional pipe structure has the following disadvantageous: when the inner tube 51 is connecting with the connecting portion 531, there is merely a tightening ring 533 outside the inner tube 51, and the outer tube 52 is only secured by the locking sleeve 54, so the structural strength is not strong and the components of the pipe may be separated when in use.
Furthermore, when the inner tube 51 is connecting with the connecting portion 531, it is secured by the tightening ring 533. When the outer tube 52 is tightened by the tightening ring 533, the tightening ring 533 surface is squeezed by the protruding unit 541 of the locking sleeve 54, so the inner tube 51 and outer tube 52 are both squeezed by the protruding unit 541. When the inner tube and outer tube are pulled to extend, the walls of the inner and outer tubes become thinner, and the inner tube and outer tube make be broken under this situation.
Also, the outer tube 52 has no resilience so when the inner tube 51 sustains the water pressure to expand to cause the outer tube 52 to increase its length, the water flow is restricted after flowing to the inner tube 10 and the water pressure drops. Therefore, there remains a need for a new and improved pipe structure to overcome the problems stated above.